Constant level immersion melting pot



July 13, 1965 E. J. FUNK, JR

CONSTANT LEVEL IMMERSIN MELTING POT Filed March 4, 1963 PLATE l msn/v6 maw/NE United States Patent O rl`his invention relates to a constant level immersion melting pot for use in the printing industry to produce stereotype plates. More particularly, the invention relates to a melting pot having a central chamber in which metal fed to it is melted and then pumped to adjacent casting chambers under conditi-ons as to maintain a sub.

stantially constant level in the casting chambers.

In modern high speed printing presses of the rotary type, such as are used for the production of newspapers, print type is supplied to the presses in the form of cast solid curved plates known as stereotype plates. Due to the great number of newsprint pages which these presses produce and the number of castings required by the size of todays newspaper editions, it is desirable to have available for casting into stereotype plates a large total volume of type metal, and in many cases it is preferable to have available enough metal to cast the print for an entire edition. The amount of metal used for each stereotype plate of course is small relative to they total amount of metal desirably in reserve. Additionally, in order to achieve a good casting in each case, there is required close control of metal temperatures and of the levels of metal in the container supplying molten metal to the casting machines. The requirement of casting a small amount of metal supplied from a container wherein close control of temperature and of the level of metal therein is desired has been generally inconsistent with maintaining a full supply of molten metal in one container at the casting machine.

The usual practice has been to employ at the casting machine a heated container called a casting pot consisting of a single chamber for containing the molten metal to be supplied to the casting machine. A metal pump at the casting machine delivers the metal from the casting pot to the casting machine. Frequently, two casting machines located at the casting pot are served from a single casting pot. When this is the arrangement, the casting machines necessarily are quite close together separated only by the width of the casting pot. This arrangement involves a cramped space utilization resulting in inetiicient and diiicult maintenance of the equipment due to poor access, which is further complicated by the need for maintaining close to the equipment a supply of make-up metal for adding to the casting pot.

It has been the practice for one of the casting machine operators to add additional metal 4to the casting pot as metal is withdrawn from it so as to maintain in the casting pot the desired level of metal to insure production of a good casting. This metal is taken from a supply of used stereotype plates returned from the presses. This hand operation is inefficient and time consuming, distracts the casting machine operator from the casting procedure and, if overloaded, results in poor casting when the metal level in the casting pot drops below the prescribed lower level. There are also the problems of maintaining at hand a suicient supply of make-up metal to be added to the casting pot and a tendency for the casting pot temperature to drop when cold metal is added to it.

In large operations, to insure a suiiicient supply of molten metal to the casting pots, provision has been made for a heated holding pot located at a distance from the casting pots in which used stereotype plates are melted. From this holding pot, the molten metal is pumped through a heated pipeline to the casting pots. This procedure requires separate units for melting the metal and casting the metal as well as the heating of a pipeline to supply the casting pots with metal.

This invention contemplates a constant level immersion melting pot in which the melting pot is divided into a central chamber for melting the metal plates being returned to it, and adjacent chambers for feeding the casting machines, the adjacent chambers being pump supplied with metal from the central melting chamber and maintained at a constant level during the casting operation.

The melting pot is in lthe form of a divided vessel which has a reserve supply melting chamber containing molten metal and one or more casting chambers adjoining it which are pump supplied with the metal from the melting chamber and maintained at a substantially constant level as the metal from it is supplied to the casting machine forming the stereotype plates. The casting chamber or chambers are each of smaller volume than the reserve supply melting chamber and are adapted for close control of the level of metal therein by operation of transfer pump. The transfer pump is actuated by a liquid level control which energizes the pump when the level of the metal reaches a predetermined lower limit, or temporarily ceases to operate when the metal level in the chamber reaches a predetermined upper limit, thus providing a substantially constant level in the casflng chambers.

Advantageously, the unitary apparatus of this invention may consist in a generally oblong lioor mounted casting pot for maintaining type metal in a molten state. The vessel may have a relatively large central melting chamber for use as a reservoir and be partitioned -across each end to form smaller chambers in the ends from which metal is supplied t-o the casting machines for forming the stereotype plates.

The walls of the pot may be suitably insulated and each chamber may be provided with means for heating the chamber and the metal in it. Any suitable heating means may be employed, for example, gas tired or electrical heating ele-ments which preferably are disposed Within the chambers so as to be partially or wholly submerged in the holten metal contained in the chambers. It will be appreciated that heating means may be disposed Within the walls of the chambers or external to them to provide the necessary temperature Within the melting pot.

For setting and maintaining the temperatures desired within the pot, the heating means for each chamber may be individually or collectively controlled by manual or automatic means or both.

The fact that the pump means and the conduit connecting the reservoir chamber with the casting chambers are within the melting pot eliminates the need for heated transfer conduits. However, the conduit for conveying the pumped metal from the reservoir chamber to the casting chamber may be positioned so that a portion `of it is not in the molten metal but extends over lthe Wall separating the chambers. In this type of arrangement the exit end of the conduit would be immersed in the molten metal in the casting chamber.

it will be appreciated that an even distribution of heat throughout the molten metal in the chambers may be provided by use of an agitating means, such as a motor driven impeller or other like circulating means. Also, any form of level sensing means may be used that will maintain the height of the molten metal in the casting chamber substantially constant so that uniform plates are produced when the metal is `supplied to thecasting machine.

ln use, when no metal is being withdrawn from thev casting chamber and its level of molten metal is within the pre-set limits, the transferpump remains out of operation. YIf metal is taken from the casting chamber sufficient to cause the level to fall to the predetermined lower limit,

the sen sin g' device acts .to energize the transfer pump to replenish tothe casting chamber from the reservoir chamber the amount withdrawn. Pump transfer of metal into the 'casting chamber 'continues until the level reaches the predetermined upper limit, -at whichV time the y'sensing 'Y means ac tst'o causethe pump to stop operation.

Advantageously, Vwhen more than one Ycastingchamber adjoinsthereservoirchamber, such casting chambersmay be, connected jbymeans for equalizing the level Vvof: metal within the c asting chambers, such as by use of an equalizing lineorpipe, This allows use of a single metal trausfer pump for maintaining substantially the same metal levels in the casting chambers 'by 'operating the pump from level controls in one of the casting chambers.

' lt vvill be appreciated that when the meltingpot is Y (see4 FIGURE 2),

separated by a space sulhcient for access to both the melting p ot and the casting machines, and operating and maintenance personnel have greater free area forV eflicient kand unhampered activity.

These and other objects,'features and advantages will become apparent by reference to the following detailed description Vand claims when read in conjunction with the accompanying drawings,'in which: Y FIGURE l Vis a'top plan view vof the melting pot of my invention'showing the melting chamberand the adjacent casting chambers for 'supplying molten metal tothe plate casting machines; and

of FIGURE '1 taken on une 2 2 of FIGURE 1.

YReferring to the drawings, a melting pot 10 `isjbounded by i'ts upstanding perimetrical wall'lZ having ends 1 4 and I6 and sides 1 3 and 2t). The pot has a closedbottom and the fperimetrical wall and bottom may be insulated `as at 24 to prevent lossv of heat fromthe 'containen The bottom, end, and sid'eso'f the'ves's'el are lined inside with' sheathing 26 'and outside with sheathing 28. The insulation may be structural in character to provide` the vkwall with the required strength, as for'example by refractory Ybrick, Vor the 'walls may otherwise be given strength, as by internal bracing, and furnished with insulation of a nonstrutural nature. 1

The meltingpot is compartmentedA interirly by posi- FIGURE 2 Vis a front elevational view of the melting pot d at theV desired temperature. It is also within the ambit of my invention to regulaterthe temperature of the charges of metal Within each chamber at the same or at differing temperature levels, depending on the heat requirements of the chambers. It will be appreciated that there may be substituted for the gas heating system any other suitable heating system,'as for example electrical heating elements. In addition, the position and size of the heating elements may be varied from that shown.

An agitation device 58 which includes motor 60 and motor guard 62 are held, by supports 645so that operation of the motor will revolve shaft 66 land its attached impeller 63 to provide for circulatory movementof the metal Zit) to distribute the heat supplied by the heating elements evenly throughout the metal' in the center or reservoir chamber to eliminate vundefrheatecl pockets of metal and prevent*i 'overheating of lthe Vindividual heating elements VTwo casting machines (details not shown) are supplied with molten metal through discharge lines 7 0 and 72 from casting machinepumps '74 and 76 operated by shafts 78 and Si) which are revolved 'b'y casting pump motors 82 and 84, respectively.V In the drawings, the casting machines, the castingmachine pumps, their motors andfdisc'harge lines are shown in dotted lines.

Metal transfer pump apparatus provides for transfer of metal from the chamber 34 to the end chambers 36 and 33 and is operated by 'transfer` pump motor 88 acting through shaft 90 onimpeller 91. Transfer of metal between the central chamber and the end chamber is through transfer line 92 which extendspbetween the central charnberand the end chamber 38. Pump apparatus 86 is energizejdin response to lower level sensing device 96 anddeenergized in response to upper level sensing device 94, which are positioned in the end chamber 38 for sensing the surface level of the metal charge 44. These devices act to' operatively control 'the metal transfer pump through control vconnections with the pump (not shown). While these level sensingdevices are shown as separate, it is understoodoffcourse thata'ny suitable sensors or vcontrols or combination thereof may be used, as for example a iioat control s uchlas an o n-oi type switch operated by a lloat buoyed at the; surfaceof the metal charge. T he metal level in 'chamber 36 is maintained atfs'ubstantially the same level as thejm'etal' in vchamber 3 '8 by passage of metal from 'the `one end chamber to theother through a level 'equalizing line '93 extending betweenthe two end chambers by passing through thecenter chamber and opening into the Vrespective lchambers throughopenings 100, and 102 in partitions 3u and 32 (see FIGURE 2).' This arrangetoning across each end 'the upright Vpartitions 30 and 32 s'o as lto divide the pot into a large center chamber 34 and smaller end chambers 36 and 38. This results in a unitary melting pot 'containing' a series of three chambers arranged in a straight line. The center chamber is adapted to` contain a supply o'f type-casting metal 40 which may be use'^ fully s uflicient for casting an entire editionfof a larfge newspaper. The end chambers are adapted to contain the respective charges of type-metal 42and 44 which issupplied from the V.respective end chamber to the adiacent casting1machi1ie46orgs, as the case may be .(see FIG-f So that the metal. may be brought to the desired't'ernperatu're tofmaintainit in 'its-molten state, there is provided a heating system for "supplyin'g heat to the metal in the various chambers in themeltingV pot.` Y This system may be gas fired heating elements positioned Within the Y respective chambers so as to be submerged in the metal. Each heatingelement may be'separately fed'fron'i fuel 1:'

header J5 2 through a controllvalve 54 and branch line S6.

The heating elements maybe operably controlled eitherV individually'or'togetlier by any suitable system of controls formaintaining the metal within Vthe respective chambers ment 1of theequalizing rline provides for maintaining it heated throughcontact with the moltenmetal charge in the center chamber,V

It will b e appreciated' that two metal transfer pumps maybe used so that eachwill-supply molten metal to a casting chamber thereby eliminating 'the necessity for the level equalizing lir 1e 98 y A c o'nyevorlltf may befemployedto return theused stereotype plates 106 from the 'presses (not shown) to the central chamber so that manual introduction lof replacementmetal isno't required.

In operatio n, t he vlevel of the molten metal in 'th'e centralchamber '325 'rises and falls as metal is" transferred by .the transfer pump from V"this chamberinto theV casting chambers, and replenishment metal is returned to it by the conveyor. As the casting `machine pumpvvithdraws metal from either Vcasting chamber, the metal level of these 'f chambers will 'fall until 'it reaches the predetermined lower limit as sensed bythe lowerlevel sensing device v9&5. When this happens, device 9 6 acts to energize the metal transfer pump 86 whichV operates to 'transfer metal from the central .chamber to the end'charnber so that 'a substantiallyl constant level ismaintained. The pump continues to operate until the metal level in the end chamber rises to the prejdetermined upper level limit as sensed fby sensing device amasar transfer pump, and the pump remains out of operation until the cycle is repeated and the metal level in the end chamber again falls to its lower limit.

It will be understood that various changes and modifications may be made without departing from the spirit and scope of my invention.

What is claimed is:

A melting pot apparatus for holding and continuously supplying hot molten metal to a plurality of metal casting machines which comprises a melting pot, said pot being divided by at least two partitions extending across the melting pot into a relatively large reservoir chamber for receiving metal to be melted and at least two smaller casting chambers immediately adjacent to said reservoir chamber, heating means positioned in said chambers for maintaining said metal in its molten state, a conduit connection between at least two of said casting chambers to equalize the molten metal level in said casting chambers, said connection being immersed entirely within the molten metal in said reservoir chamber whereby the metal passing therethrough is maintained in its molten state, pump means in each of the casting chambers for discharging molten metal therefrom to a casting machine, conduit means in communication with said reservoir chamber and with at least one casting chamber, second pump means in said reservoir chamber for supplying molten metal from said reservoir chamber through said conduit means to at least one casting chamber, and control means for maintaining a substantially constant level of molten metal in at least one casting chamber, said control means being responsive to predetermined upper and lower levels of the molten metal in said one casting chamber to energize said second pump means whereby the level of molten metal in said one casting chamber is maintained between said upper and lower levels, the second pump means in said reservoir chamber operating substantially independently of the pump means in the casting chambers whereby the transfer of molten metal to said one casting chamber is effected intermittently during continuous discharge of molten metal from said casting chambers.

2. The melting pot apparatus of claim 1 in which said conduit means is below the level of molten metal in said chambers, whereby the metal therein is maintained in a molten state by heat transfer with the molten metal in said chambers.

3. The melting pot apparatus of claim 1 in which the inlet of said second pump means is below the lower level of molten metal in said one casting chamber whereby the discharge of molten metal by the second pump means may be continuous when the level of molten metal in said reservoir chamber is below the level in said one casting chamber.

d. The melting pot apparatus of claim 1 in which the reservoir chamber has an agitator positioned in it to maintain the metal at a uniform temperature.

5. The melting pot apparatus of claim 1 in which the reservoir chamber has means for conveying metal to it to be melted.

References Cited by the Examiner UNITED STATES PATENTS 1,220,211 3/17 Feldkamp et al 266-34 X 1,934,479 11/33 Betterton et al. 266-34 2,924,234 2/ 60 Wilson a 137-392 3,056,178 10/62 Iagielski 22-70 FOREIGN PATENTS 599,111 3/ 48 Great Britain. 837,867 6/ 60 Great Britain.

OTHER REFERENCES Wood Newspaper Machinery Corporation, A new line of immersion-type gas-red soft metal furnaces, July 17,

MARCUS U. LYONS, Primary Examiner.

MICHAEL V. BRNDISI, Examiner. 

1. A MELTING POT APPARATUS FOR HOLDING AND CONTINUOUSLY SUPPLYING HOT MOLTEN METAL TO A PLURALITY OF METAL CASTING MACHINES WHICH COMPRISES A MELTING POT, SAID POT BEING DIVIDED BY AT LEAST TWO PARTITIONS EXTENDING ACROSS THE MELTING POT INTO A RELATIVELY LARGE RESERVOIR CHAMBER FOR RECEIVING METAL TO BE MELTED AND AT LEAST TWO SMALLER CASTING CHAMBERS IMMEDIATELY ADJACENT TO SAID RESERVOIR CHAMBER, HEATING MEANS POSITIONED IN SAID CHAMBERS FOR MAINTAINING SAID METAL IN ITS MOLTEN STATE, A CONDUIT CONNECTION BETWEEN AT LEAST TWO OF SAID CASTING CHAMBERS TO EQUALIZE THE MOLTEN METAL LEVEL IN SAID CASTING CHAMBERS, SAID CONNECTION BEING IMMERSED ENTIRELY WITHIN THE MOLTEN METAL IN SAID RESERVOIR CHAMBER WHEREBY THE METAL PASSING THERETHROUGH IS MAINTAINED IN ITS MOLTEN STATE, PUMP MEANS IN EACH OF THE CASTING CHAMBERS FOR DISCHARGING MOLTEN METAL THEREFROM TO A CASTING MACHINE, CONDUIT MEANS IN COMMUNICATION WITH SAID RESERVOIR CHAMBER AND WITH AT LEAST ONE CASTING CHAMBER, SECOND PUMP MEANS IN SAID RESERVOIR CHAMBER FOR SUPPLYING MOLTEN METAL FROM SAID RESERVOIR CHAMBER THROUGH SAID CONDUIT MEANS TO AT LEAST ONE CASTING CHAMBER, AND CONTROL MEANS FOR MAINTAINING A SUBSTANTIALLY CONSTANT LEVEL OF MOLTEN METAL IN AT LEAST ONE CASTING CHAMBER, SAID CONTROL MEANS BEING RESPONSIVE TO PREDETERMINED UPPER AND LOWER LEVELS OF THE MOLTEN METAL IN SAID ONE CASTING CHAMBER TO ENERGIZE SAID SECOND PUMP MEANS WHEREBY THE LEVEL OF MOLTEN METAL IN SAID ONE CASTING CHAMBER IS MAINTAINED BETWEEN SAID UPPER AND LOWER LEVELS, THE SECOND PUMP MEANS IN SAID RESERVOIR CHAMBER OPERATING SUBSTANTIALLY INDEPENDENTLY OF THE PUMP MEANS IN THE CASTING CHAMBERS WHEREBY THE TRANSFER OF MOLTEN METAL TO SAID ONE CASTING CHAMBER IS EFFECTED INTERMITTENTLY DURING CONTINUOUS DISCHARGE OF MOLTEN METAL FROM SAID CASTING CHAMBERS. 